The invention relates generally to structural elements of the type which are provided with means for connecting them to other structural elements. Of particular interest to the invention are structural elements which are useful for the construction of lattice or grid structures, and especially those structural elements which may be used for the production of toy building models.
A known structural element of the type under consideration has a square or rectangular cross-sectional configuration. The sides of the element, as well as one of the lateral or end faces, are provided with undercut connecting grooves. The other lateral face of the element is provided with an undercut connecting lug. The lug may be received on a groove of another structural element and, in this manner, the structural elements may be joined to one another.
Structural elements of this type composed of synthetic resin have been used as building blocks in toy construction sets. The building blocks are connected by pushing the undercut lug into the undercut grooves provided on the sides and one lateral face of each of the building blocks. The adjustment of the force required for sliding the undercut lug into the undercut grooves, as well as the force with which the undercut lug is held in the undercut grooves, makes it necessary to maintain very tight tolerances for the connecting elements (the grooves and lugs) during finishing of the building blocks. For this reason, it is also not possible to make the building blocks arbitrarily large as might be desired, for example, for the erection of toy building models in dependence upon the size of the children. Advantageously, building blocks of larger size, such as those used for toy building models suited for larger children, are made of wood. However, even if one were able to achieve the above-mentioned very tight tolerances during finishing of the building blocks by expending a great deal of effort for the finishing operation and, concomitantly, greatly increasing the costs, it would nevertheless be of little value due to the warping and swelling characteristics of the wood. In fact, even with a change in atmospheric conditions, the dimensions of the connecting elements provided on the building blocks can change in such a manner that a usable connection between two building blocks can no longer be obtained.